Variation

• What is meant by variation in biology?

  Variation refers to the differences in the characteristics of individuals in a population.
• What are the three main causes of variation in a population?

  The three main causes of variation are genetic causes, environmental causes, and a combination of both.
• What is an example of genetic variation in humans?

  Examples of genetic variation include hair color and eye color.
• How does the environment cause variation in characteristics?

  Environmental factors can influence characteristics, such as the color of flowers depending on soil pH.
• What is an example of variation caused by a combination of genes and the environment?

  An example is human height, which is influenced by both genetics and diet.
• What is the role of mutations in genetic variation?

  Mutations are random changes to DNA that contribute to genetic variation.
• How do most mutations affect the phenotype?

  Most mutations have no effect at all on the phenotype.
• How can a mutation influence the phenotype of an individual?

  For example, alleles for tallness may lead to tallness if the diet is suitable.
• What is a key idea about mutations and phenotypes?

  Very rarely, a mutation can lead to a new phenotype.
• What can happen if a new phenotype is beneficial in a changing environment?

  A beneficial phenotype can lead to a rapid change in the species.
• What was the example given regarding rabbits and a virus in the UK?

  A mutation made some rabbits resistant to a virus, leading to a new beneficial phenotype in the population.
• What is the significance of the mutation in the rabbit population?

  The mutation resulted in a new phenotype that became widespread in the UK rabbit population.
• What should you be able to describe by the end of the video?

  What's meant by evolution
• How does evolution take place according to the video?

  Through natural selection
• What are the types of variation in a population?

  • Genetic variation (e.g., hair color, eye color)
  • Environmental variation (e.g., flower color due to soil pH)
  • Combination of genetic and environmental factors (e.g., human height)
• How many different species of animals and plants are estimated to exist on Earth?

  Nearly 9 million
• What are the effects of mutations on genetic variation?

  • Mutations are random changes to DNA
  • Most mutations have no effect on phenotype
  • Some mutations can influence phenotype
  • Rarely, mutations can lead to new phenotypes
  • Beneficial mutations can lead to rapid species change
• What percentage of species that have ever lived on Earth are currently alive?

  One percent
• How long ago did life first develop on Earth?

  More than 3 billion years ago
• What were the first life-forms on Earth described in the video?

  Very simple, single cells
• What is the process called through which all species of living things have evolved?

  Evolution by natural selection
• What is an example of genetic variation mentioned in the video?

  Rabbits having different combinations of alleles
• What advantage do rabbits with alleles for thicker fur have in a colder environment?

  They are more likely to survive
• What happens to the alleles for thicker fur over many generations in a rabbit population?

  They become more common
• What happens when a predator, like a fox, moves into the area?

  Rabbits with better eyesight or hearing have an advantage
• How do beneficial alleles affect the rabbit population over generations?

  They become widespread in the population
• What is the definition of evolution as stated in the video?

  The change in inherited characteristics of a population over time
• What can happen when two populations of one species become so different?

  They can no longer interbreed to produce fertile offspring
• What is an example of two different species mentioned in the video?

  Normal-sized rabbits and pygmy rabbits
• Why can't pygmy rabbits breed successfully with normal-sized rabbits?

  They are so small that they cannot interbreed
• What will you find plenty of questions on in the vision world book?

  Evolution by natural selection
• What is the significance of the link mentioned in the video?

  It provides access to additional questions on evolution
• What theory did Charles Darwin develop?

  The theory of evolution by natural selection
• Why was Darwin's theory of evolution only gradually accepted?

  It challenged the belief that God created all species and lacked sufficient evidence at the time
• Who suggested that species change over time before Darwin?

  Jean Baptiste Lamarck
• What was Lamarck's idea about characteristics and inheritance?

  Characteristics that are regularly used become more developed and are passed on to offspring
• How does Darwin's theory of evolution by natural selection differ from Lamarck's theory?

  Darwin's theory states that traits beneficial for survival are inherited, while Lamarck's suggests traits developed during an organism's life are passed on
• What are the key components of Darwin's theory of evolution by natural selection?

  • Within a species, there is genetic variation.
  • Individuals with favorable traits are more likely to survive and reproduce.
  • Beneficial traits are passed on to the next generation.
• In what year did Darwin publish his theory in "On the Origin of Species"?

  1859
• What was one reason people did not accept Darwin's theory at the time?

  Many believed that God created all living organisms